Cooling water pump for automobiles

ABSTRACT

A coolant pump for liquid cooled engines where the pump casing has a chamber, a rotatable drive shaft in the pump casing, a first pole ring on the drive shaft and a second pole ring rotatably mounted in the pump chamber which has impeller blades thereon and means for hermatically sealing the pump chamber from the drive shaft and first pole ring. Means may also be included for varying the slippage between the first and second pole rings in order to vary pump output.

United States Patent 1 1 Laing 1 Mar. 27, 1973 [54] COOLING WATER PUMPFOR 2,633,697 4 1953 Johnson ..123 41.12 AUTOMOBILES 2,652,816 9 1953Dodge ..123 41.12

[76] Inventor: Nikolaus Laing, 7141 Aldingen near Primary Emmmer wimam LFreeh Stuttgart Hofener Germany Assistant Examiner-John T. Winburn 22 lMan 15, 1971 Attorney-Frank F. Scheck, S. Leslie Misrock, Merton S.Neill, Harold 'A. Traver, James W. Laist, Hal E. [21] Appl' 124,211Seagraves, Stanton T. Lawrence, Jr., J. Philip Anderegg, Clyde C.Metzger, Robert McKay, Keith E. Mul- [30] Foreign Appncafion PriorityData lenger, Robert J. Kadel, David Weild, David J. Toomey, Charles E.McKenny, Harry C. Jones, Berj Mar. 17, Austria A. Te ia John Sigalos andGerald J [52] us. C1. ..417/420, 123/41.12, 310/104, 57 ABSTRACT 415 21,416186 [51] Int Cl 1/7/00 A coolant pump for liquid cooled engineswhere the [58] Field of Search 417/420 310/104 123/41 12 pump casing hasa chamber, a rotatable drive shaft in l23/41' the pump casing, a firstpole ring on the drive shaft and a second pole ring rotatably mounted inthe pump 56 R t d chamber which has impeller blades thereon and means 1e erences for hermatically sealing the pump chamber from the UNITEDSTATES PATENTS drive shaft and first pole ring. Means may also beincluded for varying the slippage between the first and 3,324,83311/1967 Laing ..4l7/420 X econd pole rings in order to ary pump output3,4 7,469 6/1969 Laing ..4l7/42OX 3,490,379 1/1970 Laing ..4l7/420 6Claims, 6 Drawing Figures 10 l. "1 I 0 I l9 My ""11 a F I! I l I ,0 I 9r- IIQ'WI' 11. L o\\ i, I

et-"al a v I F (/77 I'III/l/ll/I l \wll I! .5

q 18 "I V 5 7 COOLING WATER PUMP FOR AUTOMOBILES BACKGROUND OF THEINVENTION For water-cooled automobile engines cooling water pumps arerequired which, in general, are driven by a V-belt drive and which aresealed by rotary axial sealing systems. Since all rotary shaft sealingspermit a certain amount of leakage to occur, however small it may be, itis necessary to add cooling water at more or less regular intervals. Assoon as damage occurs to the sealing discs with their highly accuratesliding fits, e.g., by penetration of a sand grain from the moldingsand, the cooling circuit will lose large amounts of cooling liquid in avery short time. Therefore, the shaft sealing presents a damagepotential for the automobile engine.

With combustion engines about 60 percent of their heat losses aredissipated via the exhaust gases and cooling water while another percentis dissipated to the air stream around the engine case. At idlingconditions and small engineloads the cooling water dissipation rate isrelatively large. This is because the exhaust gases escape very slowlythus transferring their heat to the cylinder walls since sufficientairstream cooling is not available to cool the engine block. Atincreasing engine speed the engine performance rate will rise to amaximum which occurs at a rate of 80 to 90 percent of the maximum speed.The cooling water minimum circulation rate, however, is, in general,achieved at about 40 percent ofthe crankshaft speed of rotation. At e.g.crankshaft speeds the circulation rate will also rise since the deliveryof the engine-driven pump continues to increase proportionally with theengine crankshaft speed, but in this condition there is no need for afurther improvement of cooling efficiency. The power consumption of arotary pump increases cubicly with its speed of rotation so that with anincrease in speed from 40 to 100 percent of maximum speed the powerconsumed by the pump will be fifteen times the value required for asufficient cooling of the engine. With a 200 HP engine, e.g., the pumpdelivery rate required for maximum engine speed would consume .5 HP,while the actual power consumption of the pump at maximum engine speedamounts to 7.5 HP; thus 7 HP are wasted.

GENERAL DESCRIPTION OF THE INVENTION The invention relates generally toa coolant pump for liquid cooled combustion engines where the driveportions of thepump, i.e., the drive shaft, are hermatically sealed offfrom the driven portions of the pump, i.e., impeller blades, toassure'that there will be no leakage of coolant around the drive shaft.The invention also relates to structure to vary the circulation rate ofthe pump and hence of the power consumed, to the amount actuallyrequired for cooling the engine. To achieve this, the invention uses apump, the impeller of which is provided with a magnetic pole ring whichis driven by a mechanically driven pole ring and which is separated fromthe latter by a hermetic sealing wall of nonmagnetic material. Sincebushings and shafts when arranged in the liquid circuit are easilyblocked by penetrating dirt particles, the invention preferablyuses polerings the magnetic poles of which face a spherical cap type separationwall with the impeller and associated pole ring rotating in the liquidcoolant being sustained by two supporting elements arranged in thegeometrical center of thespherical separting walls for counterbalancingthe magnetic axial force in the low speed range, and hydraulic thrust inthe high speed range. Furthermore, the spherical cap separation wall isprovided with a cover means so that the driving pole ring is position ina hemispheric cavity hermatically sealed from the coolant. One of thepole rings, preferably that one which forms an integral part with theimpeller, is conceived to act as an induction rotor with the eddycurrent conductor element being dimensioned to give a small slip in thelow speed range, and a large slip in the upper speed range.

A further adaptation of the pump power consumption in accordance withthe coolant circulation rate actually required for engine block heatdissipation, as suggested by this invention, may be achieved by placinga thermostat into the cooling circuit which is fitted with a suitabledevice for converting temperature variations into distance variations.These distance variations are used to change the gap between the mutualmagnetic pole rings. This invention will be illustrated by some examplesfor its practical applications, but is not limited to theseapplications.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a partial sectional view ofa coolantpump constructed according to the invention;

FIG. 2 is a cutaway plan view of the pump of FIG. 1 taken in the firstquadrant at the V-belt pulley 6, in the second quadrant at the feed pipeconnection 3, in the third quadrant at the pole ring '10 and in thefourth quadrant at the impeller blading;

FIG. 3 is an enlarged view ofa portion ofa conductor cage;

FIG. 4 is an enlarged view ofa portion of a pole ring;

FIG. 5 is a partial sectional view of a second embodiment of a pumpconstructed according to the .invention; and

FIG. 6 is a graph illustrating transmitted torque as a function of pumpspeed.

DETAILED DESCRIPTION OF THE INVENTION Referring to FIG. 1, a pump case 2is shown flanged to and an engine block 1 and has a feed pipe connection3 on its intake side. Hearings 4 and 4' support a pump drive shaft 5which forms an integral part with the V-belt drive pulley 6.

A first pole ring having a convex outer surface is rigidly mounted onthe shaft 5 and comprises a permanent magnetic material. The permanentmagnetic pole ring 7 is housed in a hemispheric case formed by thehemispheric cap 8 and a bottom cover 9 which is rigidly attached to thecase 2. Closely joining the outer contour of the hemisphere 8 a seconddriven pole ring 10 is mounted for rotation in a chamber in the pump.Pole ring 10 has a convex outer surface and a concave inner surface andcomprises a spheric cap type iron ring fitted with copper strips 11which are connected .to each other on their ends by copper rings 12and.l2' like the squirrel cage of an electric motor as shown in FIGS. 2and 3. On the convex outer surface of the iron ring impeller blades 13are arranged. On its larger diameter side the pole ring 10 is closed bya wheel disc 14 which is rigidly attached to a ball 16. The disc 9 whichon its periphery is sealed to the hemisphere cap 8 and bears the bushing15 in its center hermetically seals the cavity 18 from the pump chamber.From casing 2 spokes 19 branch into a central hub 20, which bears asecond bushing 15. The ball 16 is mounted between the two bushings 15and 15' so that the center of ball 16 approximately coincides with thecenter of the sphere associated with the hemispherical wall 8 and theconvex and concave contours pole rings 7 and 10.

The copper cage winding is further illustrated in FIGS. 2 and 3. Asshown in FIG. 3, the conductor cage may be made as a stamped copper partwith the poles of the outer ring 10 extending into punched-out areas 30of the cage.

FIG. 4 also shows the pole ring 7 made of ferro-magnetic materialextending only over half the circumference. The segments 40 and 40' areconstructed as cut-out spherical shells and cemented to each other inthe slots 41. The magnetization proceeds in the direction of thespherical radius 42, so that the convex and concave sphericalquadrangles of each sector have a different polarity. The adjacentsegments 40 and 40' also display a different polarity.

FIG. shows a design of the invention, in which the inner pole ring 50 issupported by a bellows 51. This bellows is connected through a capillarytube line with a tank 53. The interior of this system is filled with asubstance which expands greatly under the influence of heat. At a lowcooling water temperature the permanent magnetic pole ring is in theposition 54, so that a large slip is developed between this pole ringand the outer pole ring 55, which forms an integral unit with theimpeller blades 56. The permanent magnetic pole ring 50 does not movetowards the hemispherical shell 8 until the cooling water temperatureexceeds a predetermined level, whereby the transmitted torque isincreased and the slippage thus reduced. The pole ring 50 is not movedinto the indicated position until the safe cooling water limitingtemperature has been reached. Even in this position the wall 9 creates ahermetic seal between the chamber 18 and the circulating water. Thesurface of the hemispherical shell 8 is machined extremely true to form,and the convex outer pole ring, which is adapted to it exactly, glideson it. The outer pole ring remains constantly locked to form through theaxial component 58 of the magnetic forces.

FIG. 6 shows the flow of the transmitted torque as a function of speed,air gap interval and conductor resistance. Speed is plotted on theabscissa 60, while the torque is plotted on the ordinate 61. The curve62 shows the course of the pump impeller speed with a soft iron polering 10 and a cage winding with large cross section as in FIG. 3. Thecurve 63 shows the same arrangement, in which, however, the cage windingcross section 11, 12, 12 is kept considerably smaller. The curve 64shows the transmitted torque of a pump as in FIG. 5 in cold condition,in which thus the pole ring 50 is in the position 54. A similar effectto that from increasing the resistance of the cage winding 11, 12, 12'can be achieved by reducing the cross section of the iron backing 57.The air gap 50/54, the thickness of the iron backing 57 and the crosssection of the cage winding 11, 12, 12' as functions of the desiredpower flow must therefore be coordinated with each other. A

change of the slippage according to the invention can,

be achieved not onlyl by an axial shift of the entire pole ring, butalso by a s if of one of the iron short-circuit rings attached to theconcave side 43 of the pole ring.

I claim:

1. A coolant pump for liquid cooled engines, said pump comprising acasing, a chamber in said casing through which coolant is adapted tocirculate, a rotatable drive shaft journalled in said casing, a firstpole ring having a convex outer surface mounted on said shaft, a secondpole ring adapted to be driven by said first pole ring rotatably mountedin said chamber and having a convex outer surface and a concave innersurface with the concave surface thereof being positioned radiallyoutwardly of the convex surface of said first pole ring to form a gaptherebetween, impeller blades mounted on the convex surface of saidsecond pole ring for inducing circulation of coolant in said chamber, ahemispherical separating wall positioned in said gap and affixed to saidcasing, and a cover means affixed to the end of said separating wallwhich covers the end of said first pole ring to hermatically seal saidfirst pole ring and said drive shaft from said chamber.

2. A coolant pump according to claim 1 wherein one said pole ring haspermanent magnets thereon and the other said pole ring has means thereonthrough which eddy currents may be induced by movement of said permanentmagnets to form a magnetic couple between said pole rings.

3. A coolant pump according to claim 1 having in addition means forvarying the magnetic couple between the pole rings in order to varyslippage of rotation of said second pole ring with respect to rotationof said first pole ring.

4. A coolant pump according to claim 3 wherein the means for varying themagnetic couple includes means for varying the width of the gap betweenthe first and second pole rings.

5. A coolant pump according to claim 4 whereinsaid means for varying thewidth of the gap includes temperature responsive means for decreasingthe width of the gap upon an increase in coolant temperature.

6. A coolant pump according to claim 1 having in ad dition a bushingmounted by said cover means concentric with said drive shaft, a ballrotatably mounted in said bushing, and a wheel disc fixed to said balland to said second pole ring whereby said. second pole ring may pivotabout the center of said ball.

1. A coolant pump for liquid cooled engines, said pump comprising acasing, a chamber in said casing through which coolant is adapted tocirculate, a rotatable drive shaft journalled in said casing, a firstpole ring having a convex outer surface mounted on said shaft, a secondpole ring adapted to be dRiven by said first pole ring rotatably mountedin said chamber and having a convex outer surface and a concave innersurface with the concave surface thereof being positioned radiallyoutwardly of the convex surface of said first pole ring to form a gaptherebetween, impeller blades mounted on the convex surface of saidsecond pole ring for inducing circulation of coolant in said chamber, ahemispherical separating wall positioned in said gap and affixed to saidcasing, and a cover means affixed to the end of said separating wallwhich covers the end of said first pole ring to hermatically seal saidfirst pole ring and said drive shaft from said chamber.
 2. A coolantpump according to claim 1 wherein one said pole ring has permanentmagnets thereon and the other said pole ring has means thereon throughwhich eddy currents may be induced by movement of said permanent magnetsto form a magnetic couple between said pole rings.
 3. A coolant pumpaccording to claim 1 having in addition means for varying the magneticcouple between the pole rings in order to vary slippage of rotation ofsaid second pole ring with respect to rotation of said first pole ring.4. A coolant pump according to claim 3 wherein the means for varying themagnetic couple includes means for varying the width of the gap betweenthe first and second pole rings.
 5. A coolant pump according to claim 4wherein said means for varying the width of the gap includes temperatureresponsive means for decreasing the width of the gap upon an increase incoolant temperature.
 6. A coolant pump according to claim 1 having inaddition a bushing mounted by said cover means concentric with saiddrive shaft, a ball rotatably mounted in said bushing, and a wheel discfixed to said ball and to said second pole ring whereby said second polering may pivot about the center of said ball.